Photon diagnosis and photon therapy belong to two research and application development directions in the current medical photon technology, with the former taking a photon as an information carrier, and the latter taking a photon as an energy carrier. In photon diagnosis, identification of different tissues can be realized through performing real-time detection or imaging on reflected lights, transmission lights and scattered lights in the tissue or on fluorescent lights (including auto fluorescence and drug fluorescence) generated after a tissue is excited by an exciting light. In photon diagnosis, tissues are analyzed according to optical properties owned by a biological tissue. Compared with traditional surgical biopsy, photon diagnosis is a non-invasive histopathological analysis method, and can overcome a change in biochemical properties of tissues which may be caused in a surgical biopsy process; compared with such examinations as X-rays, CT and MRI, photon diagnosis can not only avoid ionizing radiation, but also realize early diagnosis of pathology. Photon therapy includes intense laser therapy, low-level (low-intensity) laser therapy and photodynamic therapy (PDT). With low-level laser radiation as an example, after an organism is radiated by a low-level laser, the laser does not directly cause an irreversible damage of a biological tissue, however, due to its own biological stimulus effect, a radiated tissue generates a “responsive” response to this stimulus. On a molecular level, synthesis of protein and nucleic acid is adjusted, replication of DNA is influenced, and the function of enzyme is adjusted; and on a cellular level, it is a process of removing pathology through mobilization, compensation, nutrition, repairing, immunity and other regenerative or defense mechanisms.
In recent years, along with an increasing maturity of nanotechnology and related interdisciplines, an application of the nanotechnology in medical science has revealed its importance for the first time. Many molecular markers which are applied to diagnostics and therapeutics respectively are integrated to form theranostics. Based on an important role of a photon technology in medical diagnosis and therapy, photonic theranostics, a brand-new research direction, is gradually formed, which is also a trend towards medical personalized development in the future. With photodynamic therapy (PDT) as an example, the target is to develop a nano particle platform which takes photosensitizer molecules as a core. The platform integrates active targeting delivery of medicines, diagnosis of tumors (such as MRI and molecular fluorescence imaging), therapy (hyperthermia therapy and PDT), dose monitoring (singlet oxygen probes and oxygen molecule probes), and therapeutic effect evaluation (cell apoptosis probes, MRI and biochemiluminescence), thereby fully reflecting advantages and potential applications of modern nanomedicine.
As an important means of diagnosis and therapy, the biggest drawback of photon is that visible lights and near-infrared lights cannot penetrate deep into human tissues, and now diagnosis and therapy can only be performed on a body surface and on surfaces of larger cavities of a human body (for example, esophagus). In order to solve the problem, a photon diagnosis and therapy device and method, which can penetrate deep into a human body and reach a lesion site and which will not cause greater damages to the human body, are needed.